Neanderthals, extinct hominids from Eurasia, also had an intimate life. They formed small communities of related individuals where, like any human, they protected themselves from the cold, shared food, loved, rested, cared for their children and died. They probably also protected themselves from strangers and resolved their own conflicts. Now, thanks to genetics, we can learn more about how these groups were organized, who their members were, and who was new to the clan.
Researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig (Germany) have sequenced the DNA of the bones of thirteen Neanderthal men, women and children from between 51,000 and 59,000 years ago, found in two caves in the Altai mountains, in Siberia (Russia). ).
The genetic study, the largest known of this human species to date, recognizes a father with his teenage daughter, a couple of second-degree relatives who may be uncles, grandparents or cousins, and women from other groups, who knows. whether by force or willingly. Released in the magazine ‘Nature’, it is the portrait of the oldest known human ‘family’ that has been identified by its genetic ties.
Since Svante Pääbo, the last Nobel laureate in Medicine and co-author of this study, succeeded in unraveling the Neanderthal genome in 2010, data have been recovered from the entire genome of 18 Neanderthals, thus thirteen more, and in addition to the same place and chronological time. They are a significant milestone. Eleven of the new genomes correspond to remains of individuals recovered in the narrow Chagyrskaya cave, while the other two were unearthed in another nearby, Okladnikov.
inbreeding
Among the individuals found at Chagyrskaya are members of a nuclear family: a father and his teenage daughter, and a couple of second-degree relatives (those who share about 25% of their DNA): a boy and an adult woman, perhaps a cousin, aunt or grandmother.
A male individual, related on the mother’s side to the aforementioned father, was also identified due to a genetic phenomenon called heteroplasmy. These are two versions of mitochondrial (maternally inherited) DNA that coexist for only a few generations, and therefore individuals sharing heteroplasmy are expected to be recently related along the female line. The authors believe that these two men could have shared a grandmother. Furthermore, Chagyrskaya’s genomes contain signatures of inbreeding, in the form of long stretches of identical DNA inherited from each parent.
Still, it is unclear whether this level of inbreeding was common among Neanderthals, or a specific feature of Altai populations, isolated on one geographical edge. Neanderthal populations were few and small, made up of groups of ten to thirty members. The authors compare them to the endangered mountain gorillas, a subspecies that in recent decades has comprised fewer than 1,000 individuals.
female migration
But Neanderthals did not live in completely isolated communities. By comparing the genetic diversity on the Y chromosome, which is inherited from father to son, with the diversity of mitochondrial DNA, which is inherited from mothers, the researchers found that the latter was much greater. This suggests that it was the women who frequently migrated from one clan to another, while the men tended to remain in their original nuclear family. This practice, called patrilocality, was already recognized among the Neanderthals at the El Sidrón site in Asturias.
“This is a very powerful, first-class study, but its conclusions come to ratify what our team already proposed -in the journal ‘Proceedings of the National Academy of Sciences (PNAS) in 2010- in El Sidrón: that groups Neanderthals are very small and it is the women who move from one group to another”, says Antonio Rosas, researcher at the CSIC and director of the Paleoanthropology Group of the National Museum of Natural Sciences. «This strategy, very common in human groups, allows genetic exchange to reduce inbreeding and the establishment of kinship networks. If a daughter of mine goes to another group that lives on the other side of the mountains, it is very possible that she will have relations with them and a cultural exchange will take place, ”he explains.
The new study speaks of the “first genetically identified family” -the community of El Sidrón was not-, but Rosas prefers to speak of a kinship group, “because the word family has a cultural meaning” and the relationships between them “may not be correspond to the concept of family that we have today.
No relation to Denisovans
Still, the occupants of both caves spent their days hunting mountain goats, horses, bison, and other animals, and gathering raw materials for their stone tools tens of miles away. In Chagyrskaya, where they enjoyed the hunted prey, approximately 90,000 stone artifacts have been found.
Chagyrskaya cave in Siberia
Both groups were closely related and appeared to be part of a larger population: the descendants of a later expansion of Neanderthals from Eastern Europe into Siberia, distinct from the earliest occupants of Denisova Cave, just 100 kilometers to the east and where Another hominin, a cousin of the Neanderthals, was discovered in 2010. Although both species were present in the region for hundreds of thousands of years and it is known that they even interbred, there was no gene flow from members of this clan with the Denisovans.
Benjamin Peter, co-author of the paper, says: “Our study provides a concrete picture of what a Neanderthal community might have looked like.” In his opinion, “it makes Neanderthals look much more human.”